The present invention relates to improvements in a parts assembling method by which parts are successively set to a work and then assembled therewith.
As a parts assembling method of the type above-mentioned, there is known a method as shown in FIG. 4. More specifically, a worker 1 sets a first part to a work at a predetermined position thereof in a first station A, and the first part is then welded to the work by welding robots 2 in a second station B, so that the first part is assembled with the work. In a third station C, a worker 3 sets a second part to a predetermined position of the work with which the first part has been assembled, and the second part is welded to the work by welding robots 4 in a fourth station D, so that the second part is assembled with the work. In a fifth station E, a worker 5 assembles, with bolts, a third part to the work with which the second part has been assembled.
In the parts assembling method above-mentioned, while a variety of operations are carried out on a work placed on a jig truck a, the work as placed on the jig truck a is successively conveyed from the first station A to the second station B, from the second station B to the third station C, from the third station C to the fourth station D, and from the fourth station D to the fifth station E.
Accordingly, the jig truck a has (i) means for setting a first part to a work at a predetermined position thereof, (ii) means for holding the work with which the first part has been assembled, (iii) means for setting a second part to the work with which the first part has been assembled, and (iv) means for holding the work with which the second part has been assembled.
In the conventional method above-mentioned, in order that a variety of operations are concurrently carried out at all times in the first to fifth stations to make the most efficient use of the working facilities and workers, it is required to dispose five jig trucks a, as shown in FIG. 4, each of which has the holding means and setting means as above-mentioned.
Further, there are cases where the holding means and setting means above-mentioned get in the way of the operations of industrial robots or the like.
As discussed in the foregoing, the conventional parts assembling method disadvantageously presents an increase in the cost of a parts assembling line because a number of jig truck a are required and each jig truck a has different types of means. Particularly, to cope with such recent requirements as to produce small amounts of a number of different types of articles, it is inevitable that a parts assembling line is considerably increased in cost.
Further, the holding means of the same type and the setting means of the same type disposed at the jig trucks a inevitably vary in precision, resulting in variations in the precision of final products obtained.